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Product

Neutrally buoyant ROV excursion tetherISO 13628-5Neutrally BuoyantUp to 4,000 m

ROV Tether CableNeutrally buoyant polyaramid-reinforced electro-optical TMS-to-ROV excursion tether

Neutrally buoyant subsea tether engineered for Tether Management System (TMS) drums and free-swimming ROVs to 4,000 m depth, combining 1.0–3.3 kV power cores, bend-insensitive G.657.A2 fibres and torque-free polyaramid braid.

Water-resistant
Anti-torsion braid
EMC screen
Oil-resistant
Order designation
RTC-TMS-3X6.0-8FO
Nominal OD
24.8 mm
Weight in air
490 kg/km
Weight in sea
5 kg/km
Breaking load
75 kN
All sizes (12)
Request a quoteDatasheetWhatsApp
Engineering reply in 2 business hoursCut-to-length export drumsEN 10204 3.1 certificate per drum
Rated voltage
0.6/1–3.3 kV
Observation & work-class ROV excursion
Buoyancy
Neutral ±2 %
Syntactic foam matrix in 1,025 kg/m³ sea
Design depth
Up to 4,000 m
Crush-resistant syntactic flotation
Breaking load
15–120 kN
Torque-balanced polyaramid fibre braid
Min. bend R
10 × OD
Tight TMS drum & pinch-wheel drives
Outer jacket
Yellow TPU
High-visibility abrasion & cut resistant

Typical values for this cable type, based on ISO 13628-5 / IEC 60794-3 / IMCA R 004 — confirmed in the datasheet and quotation for your order.

Application fit

Is ROV Tether Cable right for your machine?

Designed for horizontal subsea excursion from a TMS cage or surface launch where zero tether weight in water prevents seabed snagging.

Immersion & wet locations

Suitable

Syntactic microsphere flotation matrix maintains neutral buoyancy down to 4,000 m hydrostatic pressure.

Cylindrical / multi-layer drum

Suitable

Flexible construction and tough outer TPU skin withstand multi-layer TMS drum spooling and pinch-wheel tensioners.

Trailing & towing

Suitable

Slightly positive or neutral buoyancy in seawater keeps the tether clear of subsea structures and seabed hazards.

Vertical / spreader reel

With conditions

Suitable for shallow observation ROV launch; deepwater vertical cage lift requires steel-armoured ROV Main Lift Umbilical.

Use ROV Main Lift Umbilical

Fixed installation

Not suitable

Subsea flotation tether is engineered for immersed ROV excursion; derate current heavily if operated in air.

Ask engineering
Typical machinesWork-Class TMS ExcursionObservation & Inspection ROVsSubsea Pipeline & Platform NDTOffshore Wind Jacket InspectionScientific Deep-Submergence

Construction

Layer by layer

Representative work-class TMS tether: 3×4.0 mm² (3.0 kV) +earth + screened pairs + optical tubes + syntactic flotation + polyaramid braid + yellow PUR sheath.

123456
Schematic, not to scale — generated from the layer data
#LayerMaterial & reference
1Flexible power & signal coresExtra-flexible Class 5/6 tinned copper power cores (1.5–16 mm²) + screened telemetry pairsWithstands high-cycle reverse bending through TMS level-wind sheaves
2Optical fibre sub-unitsGel-filled PBT or laser-welded 316L microtubing with ITU-T G.657.A2 bend-insensitive single-mode and OM3 fibresZero macro-bending loss on compact TMS drums
3Low-density dielectricCrosslinked polyolefin / water-tree-retardant EPR power insulation & cellular PE signal insulationMinimises core mass to aid neutral buoyancy balance
4Syntactic buoyancy layerClosed-cell syntactic glass-microsphere elastomeric flotation jacket extruded over water-blocked core bundleProvides crush-resistant positive buoyancy at 3,000–4,000 m depth
5Polyaramid tensile memberOpposing-angle braided high-modulus polyaramid yarn (non-metallic, zero-torque)Delivers 15–120 kN breaking strength without adding submerged weight
6High-visibility outer jacketSubsea-grade yellow or orange hydrolysis- and tear-resistant polyether PUR outer skinHigh camera visibility and resistance to TMS traction wheel wear

RTC-OBS (Observation Class)

Slim 9.5–16.5 mm OD neutrally buoyant tether for free-swimming inspection ROVs (300–1,000 m depth)

RTC-TMS (Work-Class TMS Excursion)

Heavy-duty 20–36 mm OD 3.0/3.3 kV TMS excursion tether with syntactic foam rated to 3,000–4,000 m depth

Technical data

Ratings & operating limits

Typical values: Typical values for this cable type, based on ISO 13628-5 / IEC 60794-3 / IMCA R 004. Values for your order are confirmed in the datasheet and quotation.

Electrical

Rated voltage
600/1000 V (Observation) · 1.8/3.0–3.3 kV (Work-Class)
AC routine test voltage
3.5 kV AC (LV) / 6.5 kV AC (3 kV grade)
Insulation resistance
≥ 500 MΩ·km at 20 °C
Conductor stranding
IEC 60228 Class 5 / Class 6 tinned copper
Telemetry impedance
100 Ω / 120 Ω screened twisted pairs

Thermal

Subsea operating temperature
−5 °C to +50 °C (immersed)
Deck & TMS storage range
−30 °C to +70 °C
Max. conductor temperature
+90 °C

Mechanical

Specific gravity in seawater
1.00 to 1.03 (neutral to slightly negative/positive)
Design water depth
1,000 m (OBS) · 3,000 m to 4,000 m (Work-Class TMS)
Min. breaking load (MBL)
15 kN to 120 kN (polyaramid braid)
Safe working load (SWL)
3 kN to 30 kN
Min. bend radius (dynamic)
10 × OD over TMS pinch wheels & sheaves
Min. bend radius (static)
6 × OD

Optical

Fibre specification
ITU-T G.657.A2 bend-insensitive SM & OM3 MM
Fibre count
2 to 12 fibres
Attenuation (1310 / 1550 nm)
≤ 0.38 dB/km / ≤ 0.25 dB/km

Resistance

Hydrostatic buoyancy retention
≤ 3 % buoyancy loss at rated depth (syntactic matrix)
Abrasion & tear resistance
DIN ISO 4649 ≤ 35 mm³ polyether TPU skin
Water blocking
Silicone/polyisobutylene water-blocked interstices
Seawater & UV
Continuous immersion and tropical deck exposure

Reference standards

Design specification
ISO 13628-5 / API Spec 17E
ROV tether guidance
IMCA R 004 / DNV-ST-E402
Optical test standard
IEC 60794-1-21 / ITU-T G.657.A2

Identification

Outer jacket colour
High-visibility Subsea Yellow (RAL 1021) or Orange
Length marking
Contrast distance marks every 1 m / 5 m for TMS payout
Customs tariff (HS)
8544.70 / 8544.49

Sizes

12 standard observation & work-class ROV tether configurations

Typical outer diameter, weight in air, near-zero weight in seawater (1,025 kg/m³), and polyaramid breaking loads.

Dimensions, buoyancy & tensile ratings
Order designationElectrical + Optical CoreVoltage
kV		Nominal OD
mm		Weight in air
kg/km		Weight in sea
kg/km		SWL
kN		MBL
kN		Min. bend R
mm		Enquiry
Observation & Light Inspection ROV Tethers (0.6/1 kV)
RTC-OBS-2X1.5-2FO2×1.5 + 2×2×0.34 + 2FO1.09.876-23.51598
RTC-OBS-2X2.5-4FO2×2.5 + 2×2×0.5 + 4FO1.012.2118-35.022122
RTC-OBS-3X2.5-4FO3×2.5 + 3×2×0.5 + 4FO1.014.5166-47.030145
RTC-OBS-3X4.0-6FO3×4.0 + 4×2×0.5 + 6FO1.016.8224-39.038168
RTC-OBS-4X4.0-6FO4×4.0 + 4×2×0.75 + 6FO1.018.6276211.045186
Work-Class TMS Excursion Tethers (3.0–3.3 kV)
RTC-TMS-3X4.0-6FO3×4.0 + 1G4.0 + 2×2×0.75 + 6FO3.021.5368414.060215
RTC-TMS-3X6.0-8FO3×6.0 + 1G6.0 + 3×2×0.75 + 8FO3.024.8490518.075248
RTC-TMS-3X10-8FO3×10 + 1G10 + 3×2×1.0 + 8FO3.028.4642822.090284
RTC-TMS-3X10-12FO-333×10 + 3×4.0G + 2×2×1.0 + 12FO3.330.27251024.0100302
RTC-TMS-3X16-12FO3×16 + 3×6.0G + 3×2×1.0 + 12FO3.333.68951226.0110336
RTC-TMS-3X25-12FO3×25 + 3×6.0G + 4×2×1.0 + 12FO3.337.21,1051830.0125372
RTC-TMS-6X6.0-12FO6×6.0 + 1G6.0 + 2×2×1.0 + 12FO3.031.8802925.0105318
  • Typical values for this cable type; dimensions and weights for your order are confirmed in the quotation.
  • Negative Weight in sea (kg/km) indicates slight positive buoyancy in 1,025 kg/m³ seawater; custom trim available for fresh water or high-salinity basins.

Quality & approvals

Testing & inspection

Routine tests on every production length, sample and type tests per batch — documented on an EN 10204 3.1 inspection certificate.

  1. ConductorClass 5 stranding
  2. Spark test100 % in-line
  3. Lay-upCores, earth, fillers
  4. SheathingInner, braid / screen, outer
  5. Electrical testsAC voltage, resistance
  6. DimensionsOD, wall thickness
  7. Inspection documents & dispatchDrum & dispatch
Testing & inspectionTest value / referenceFrequency
Routine tests
AC dielectric & insulation resistance test3.5 kV AC (1 kV grade) / 6.5 kV AC (3 kV grade) for 5 minEvery tether length
Submerged weight & specific gravity verificationConfirm neutral buoyancy within ±15 kg/km target windowEvery production length
Sample tests
Hydrostatic pressure cycling test40 MPa pressure hold with live OTDR optical monitoringQualification sample
TMS pinch-wheel & reverse-bend fatigue test25,000 cycles over 10 × OD sheaves at working tensionType approval

Inspection certificate

Issued with every drum, listing the routine test results for that length.

Product approvals

ISO 13628-5 Subsea Tether CompliantITU-T G.657.A2 Bend-Insensitive Optical Core

Company certificates

ISO 9001ISO 14001ISO 45001VDE marks approvalUL / cULCE · LVD / EMC

Marking & supply

Ordering & delivery

Sheath marking

TEBAOFLEX RTC ROV NEUTRAL TETHER ISO 13628-5 [CONFIG] [METRE MARK]
Delivery form
Spool-ready export reels sized to TMS bail/drum geometry
Standard excursion lengths
150 m · 250 m · 300 m · 450 m · 600 m · 1,000 m
Buoyancy tuning
Selectable seawater (1.025 g/cm³) or freshwater (1.000 g/cm³) trim
Lead time
4–6 weeks ex-works

Technical documents

Downloads

PDFROV Tether Cable – technical datasheet12 sizes · construction, technical data, approvalsXLSXROV Tether Cable spec data (Excel)All 12 sizes with dimensions and data, for your BOM or quotation
Revision
2026-10-20
Updated
2026-10-20

FAQ

Questions engineers ask first

Not covered here? Send your drawing — an engineer replies within 2 business hours.

How does ROV Tether Cable remain neutrally buoyant at 3,000 to 4,000 m depth?
Unlike gas-blown foam that compresses under hydrostatic head, our deepwater TMS excursion tethers use incompressible hollow glass microspheres compounded into a syntactic elastomer layer, combined with low-density polyaramid tensile fibres instead of steel armour.
Can the tether buoyancy be trimmed slightly positive or slightly negative?
Yes. Free-swimming observation ROVs usually prefer 2 to 5 kg/km positive buoyancy so the tether floats above seabed obstacles, whereas work-class TMS excursion tethers are often trimmed neutral to slightly negative (+4 to +12 kg/km in seawater) according to operator preference.
Why are ITU-T G.657.A2 fibres specified instead of standard G.652.D fibres?
TMS cages wind the excursion tether onto compact multi-layer drums and through tight guide rollers. G.657.A2 bend-insensitive single-mode fibres maintain low optical attenuation at 1550 nm even under tight bend radii and pinch-wheel compression.
How is the polyaramid strength braid terminated at the ROV and TMS ends?
The opposing-angle polyaramid braid is potted into a stainless-steel or titanium socket cone using two-part marine epoxy resin, transferring 100 % of the axial pulling load to the mechanical termination while electrical and optical cores pass into the oil-compensated junction box.

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ROV Tether Cable

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